A few Questions on the DOHC head Swap

[mrg7243]

Sorry i know this has been discussed before but its just not clear enough for me, I would like to swap to and evo head, would i have any issuses with clearence between the pistons and head, or would i have to get new pistons, i would like to stay NA for awhile until i can go turbo. Also would i need an EVO ecu or would a stock ECU work fine???? Also would i be able to use and 2.0l lancer head??

[mko]

I think you should be fine with clearance.

No need of turbo ECU if you dont have a turbo, stock is fine.

2.0L Lancer head is SOHC almost similar to the one you have, so no point to do that.

[mrg7243]

SOrry i didnt specify it is a DOHC

[mko]

then yes it will fit

[mrg7243]

so it would be the same as a regular evo head swap, and i would not need pistons correct??, is basically sounds like pull and drop with a few modifacations?? Also what would it take to do a mivec head??

[Boosted]

Sorry i know this has been discussed before but its just not clear enough for me, I would like to swap to and evo head, would i have any issuses with clearence between the pistons and head, or would i have to get new pistons, i would like to stay NA for awhile until i can go turbo. Also would i need an EVO ecu or would a stock ECU work fine???? Also would i be able to use and 2.0l lancer head??

so it would be the same as a regular evo head swap, and i would not need pistons correct??, is basically sounds like pull and drop with a few modifacations?? Also what would it take to do a mivec head??

IMO, you should reprogram your current ECU or run an Evo ECU due to the fact that you will be running a DOHC head over a SOHC. As far as I know the Lancer head wouldn't be compatible so throw that out the window. This is a direct swap. You can use the stock pistons from an Evo head.


The MIVEC head swap isn't worth it IMO unless you plan on spending big money for specially produced cams, cam gears, and other power adders since there aren't alot of mass produced aftermarket items for the MIVEC platforms. And you also have to take in account that these motors haven't been proven to bolt up to our transmissions as of yet.

[mrg7243]

IMO, you should reprogram your current ECU or run an Evo ECU due to the fact that you will be running a DOHC head over a SOHC. As far as I know the Lancer head wouldn't be compatible so throw that out the window. This is a direct swap. You can use the stock pistons from an Evo head.


The MIVEC head swap isn't worth it IMO unless you plan on spending big money for specially produced cams, cam gears, and other power adders since there aren't alot of mass produced aftermarket items for the MIVEC platforms. And you also have to take in account that these motors haven't been proven to bolt up to our transmissions as of yet.

Thanks man for the mivec info it was well needed. DO you by chance know what the compression ratio roughly would be with the DOHC, my boy seems to think it will lower it since it comes off a turbo car.

[mysticj]

Depends on which 4G64 you have: Some are 9.0:1CR while others are 9.5:1CR. Also depends on which DOHC head you use.

[mrg7243]

Ok since i dont know my compression ration would it lower or raise it from stock??

[mysticj]

depends on the which DOHC head you use

[mrg7243]

i would be using an evo

[duh2150]

It would raise your comp to around 10.5:1 so if your planing on using the evo head plan to buy some pistons

[mrg7243]

i woulnt need to if i run na?? i know for boost i would need and 8.5-8.7:1 ratio, and the 8.5:1 pistons they make are they for the SOHC??

[duh2150]

who make? anyways if you put the head on there your going to have to take it back off to change out the pistons, i don't think the na lancers are even a 4g63, i think you need to go back and do more research, because you keep bringing up SOHC, it most likely will not fit, no one tried and no one has parts for a 4g64 with 4g69 head if they do id be really surprised, just go with a KIA head keep the stock pistons and boost a little

and you need custom 4g64 pistons nothing else, no evo pistons no lancer pistons, just 4g64 pistons if you wanna go NA all the way add in some kia pistons i don't think anyone tried it yet it will have you at like 12:1 CR, but that might not work

[mrg7243]

Eventually one day i would like to go to boost, and with a 10.5:1 compression ratio boost would be outta the question for awhile, i like to keep head not lift them. The reason i said SOHC is that they make 8.5:1 pistons for the stock 4g64. But since i am wanting to put an evo head on there it would raise the compression ratio from 8.5:1 to whatever. i am saying this baised upon what you said, stock compression ratio is around 9.0:1, dropping evo head on bring it up to 10.5:1. thus raising the compression.

honestly taking the head off to do pistons does not bother me.

why would i not be able to use 87.5mm evo piston, if i am not mistaken that is the bore of our motors??? so using an evo piston with an evo head would give me a stock evo compression ratio. of roughly 8.5:1. isnt this what most evo guys do?? get our block our crank and rods and use their pistons with their head, giving them a higher torque motor along with literage??

[Stewi]

Its not that simple. Buy the correct pistons for the setup your doing, the 4G64 block is taller, the piston at TDC sits at a different height than the EVO, the wrist pin is in a different location, its not the same piston, get the RIGHT piston for your setup. Using larger bore EVO pistons has been covered a hundred times and nothing has changed, you still cant use them.

[mrg7243]

SO i take it the right piston would be custom? since the standard 8.5:1 would be too high with and evo head??

[mko]

I dont see how the Evo head will raise that much. I mean the stock CR is 9.0:1 and to go to 10.5:1 is very weird. Even if it goes to 10.5:1 it will be awesome for NA driving and youll still be able to boost it with smaller turbo and run 8-10psi.

My believe is that CR wont go over 10:1.

[Stewi]

I dont see how the Evo head will raise that much. I mean the stock CR is 9.0:1 and to go to 10.5:1 is very weird. Even if it goes to 10.5:1 it will be awesome for NA driving and youll still be able to boost it with smaller turbo and run 8-10psi.

My believe is that CR wont go over 10:1.

It has to do with combustion chamber volume. The volume of the combustion chamber on the EVO head is smaller than volume of the SOHC head, this is what causes the increase in compression ratio.

[Galant306m]

Yea it only should just by about 1.0:1 at most.

I hope you know that the pistons you are going to be looking for are not going to be custom right? Manley makes a really nice set for a good price and all 4g64 blocks have the same bore so even if you find one that says application for a 1996 eclipse spyder it will still work cause its the same piston.

Kia head is basically the same thing as the evo head minus mivec and minus the evo cams, and most likely smaller intake and exhaust ports and valves which could be fixed by having the head ported and putting in evo cams and valves. Mivec is pointless to me, really so go with a evo 8 head or the kia head and you will be happy.

the 4g69 head will not work because the head is narrower and the bolt pattern is not the same so move away from that idea right now unless you want to plug and and retapp the block.